Bobcat:
I went back to take a look at that handbook thing that lists the Duke 2001 class profile. Yes you are right! They have it in there that the average matriculating MCAT was 36 for the 2001 entering class; GPA was 3.75; and average age was 21.5. Wow! Impressive yet intimidating.
You are also right that the 2002 US News ranking says the average accepted MCAT there is about 34.5. It turns out that the 2002 US News stats were computed using the stats of the 2000 entering class. In the same vein, this year's US News ranking's (2003 ranking's)accepted MCAT data will be computed using stats of the 2001 entering class.
For somewhat justifiable reasons such as residency placement and the like, several people take rankings into consideration when deciding between schools. It turned out that Duke jumped in the rankings last year from 6th(?) to 3rd. As a result, less people (than usual) chose the Stanfords, Yales, Columbias, WashUs, and Penns over Duke. So Duke's waitlist barely moved. I think this might help explain the significant increase in matriculating MCAT scores.
The above hypothesis is probably seriously flawed, but I think there might also be some truth to it.